1. Field of the Invention
The present invention relates to a cop changing mechanism for each of a plurality of winding units of an automatic winder, arranged in a row, for feeding a full cop to a winding position in each winding unit and, at the same time, removing empty bobbin from the winding unit, and also relates to an unwinding assisting device for cops successively fed to a winding position.
2. Relation Art Statement
A known automatic winder winds up a plurality of cops produced by, for example, a ring spinning frame successively in a package, such as a cone or a cheese, eliminating defective portions, such as slubs, of the yarns. Such an automatic winder has a plurality of winding units arranged in a row. FIG. 7 shows one of the plurality of winding units.
Referring to FIG. 7, a winding unit 101 is fixedly positioned by a support pipe 102 and a duct 103. A yarn Y unwound from a cop 4 located at a predetermined position in the winding unit travels through a balloon breaker 106, a disk or gate tension device 107 for controlling the tension of the yarn Y and a slub catcher 108 for detecting defective portions in the yarn Y and is taken up on a yarn package 114 rotated by a traverse drum 113. The winding unit 101 is provided with a yarn joining device 115, a suction pipe 116 for taking an upper yarn, namely, a yarn extending from the yarn package, to the yarn joining device 115 and a relay pipe 117 for taking a lower yarn, namely, a yarn extending from the cop, to the yarn joining device 115. An automatic winder has a plurality of such winding units 101. Cops 4 are supported in an upright position respectively on trays 5 arranged on a cop feed conveyor 1. Each tray 5 supporting the cop 4 is transferred from the cop feed conveyor 1 through a cop changing mechanism 3 to a winding position 11 to replace an empty bobbin 8, and then the empty bobbin 8 is transferred from the winding position 11 through the cop changing mechanism 3 onto an empty bobbin conveyor 2.
The cop changing mechanism 3 is such as disclosed in Japanese Patent Laid-open (Kokai) No. Sho 59-69370. The cop changing mechanism 3 will be described with reference to FIGS. 8 and 9. FIG. 8 shows one of a plurality of winding units 101 arranged at regular intervals in a row perpendicular to the paper. A cop feed conveyor 1 is extended along the row of the winding units 101, an empty bobbin discharging conveyor 2 is extended along the row of the winding units 101, and cop changing mechanisms 3 are disposed between the cop feed conveyor 1 and the empty bobbin discharging conveyor 2. The cop feed conveyor 1 conveys trays 5 respectively supporting cops 4. Each tray 5 has the shape of a hollow disk and is provided coaxially with a stepped portion 6. A peg 7 is set upright on the stepped portion 6. The take-up tube 8 of the cop 4 is put on the peg 7 so that the cop 4 is held in an upright position on the stepped portion 6 (as used herein, the terms "bobbin" and "take-up tube" are synonyms and are used interchangeably). A through hole 10 is formed in the upper end of the peg 7 so that the interior of the tray 5 communicates with the center bore 9 of the take-up tube 8 by means of the through hole 10. The free end Y of the yarn of the cop 4 is suspended in the bore 9 of the bobbin 8 from the upper end of the take-up tube 8. The cop feed conveyor 1 and the empty bobbin discharging conveyor 2 are extended, respectively on different levels, and the cop changing mechanism 3 is disposed along a slope between the cop feed conveyor 1 and the empty bobbin discharging conveyor 2. The cop 4 is transferred from the cop feed conveyor 1 to a winding position 11 in the cop changing mechanism 3, the yarn of the cop 4 is taken up on a yarn package, not shown, by the winding unit 101, and the empty bobbin 8 is transferred from the winding position onto the empty bobbin discharging conveyor 2.
Referring to FIG. 9 showing the cop changing mechanism 3, a first guide plate 13 and a second guide plate 14 are disposed fixedly in the winding unit 101 so as to form a bent passage 12 along which the tray 5 travels. An inclined rotary disk 15 defines the lower surface of a feed passage 12a, and a portion of the first guide plate 13 is bent to form a bottom plate 16 defining the lower surface of an ejecting passage 12b. The cop feed conveyor 1, the inclined rotary disk 15, the bottom plate 16 of the first guide plate 13 and the empty bobbin discharging conveyor 2 are included substantially in a plane. The inclined rotary disk 15 is partially in contact with the cop feed conveyor 1 and is driven for turning in the direction of the arrow a on a shaft 17. A third guide plate 18 is disposed in connection with the cop feed conveyor 1 to guide some of the trays 5 being conveyed in the direction of the arrow b by the cop feed conveyor 1 into the feed passage 12a and to allow the rest of the trays 5 to be conveyed further in the direction of the arrow b.
A stopper lever 20 provided at its free end with a free roller 19 is supported for swing motion by a shaft 21 on the first guide plate 13. The stopper lever 20 is biased in the direction of the arrow c by a spring 22 and the turning of the stopper lever 20 in the direction of the arrow c is limited by a pin 23. The stopper lever 20 has a projecting portion 25 that projects into the outlet of a first bend of the passage 12 defining a waiting position 24 to restrict the width of the outlet of the waiting position 24 to a width smaller than the diameter of the stepped portion 6 of the tray 5 when the stopper lever 20 rests on the pin 23 to keep two trays 5 always in the feed passage 12a.
An ejecting lever 26 is supported for turning by a shaft 28 on the second guide plate 14. The ejecting lever 26 has a recess 31 for receiving the stepped portion 6 of the tray 5 to hold the tray at the winding position 11 corresponding to a second bent portion of the passage 12, and a roller operating edge 32 having the shape of an arc of a circle having its center on the center axis of the shaft 28. As shown in FIG. 8, the shaft 28 of the ejecting lever 26 is turned by a rocking arm, not shown, reciprocated by a push rod 44 moved vertically by tray moving cams 43.
Since the winding position 11 is located on the inclined rotary disk 15, the inclined rotary disk 15 is provided with a plurality of circular slots 34 having the shape of a circular arc having their centers on the center axis of the shaft 17. When the tray 5 is located at the winding position 11, the center axis of the peg 7 coincides with the circular slot 34. As shown in FIG. 8, a nozzle 35 for blowing compressed air through the circular slot 34 into the bore of the peg 7 is disposed under the inclined rotary disk 15. The nozzle 35 is connected via a valve 38 controlled by a lever 37 for opening and closing to an air hose 36. When a shaft 39 is turned to open the valve 38, air supplied through the air hose 36 is blown from the nozzle 35 through the circular slot 34, the interior of the tray 5 and the through hole 10 of the peg 7 into the center bore 9 of the bobbin 8 to blow the free end Y1 suspended in the center bore 9 upward and, consequently, the free end Y1 is blown up through the balloon breaker 106 of the winding unit 101 and is caught by suction by a suction pipe, not shown, disposed above the balloon breaker 106. Then, the free end Y1 is pieced to the free end of the yarn being wound on the package, not shown. The shaft 39 of the lever 37 is turned by the rocking arm, not shown, reciprocated by the push rod 45 moved vertically by the tray moving cam 43.
The operation of the prior art cop changing mechanism 3 will be described hereinafter. Referring to FIG. 9 showing the cop changing mechanism 3 in a state for the normal winding operation, a first tray 5a is located at the winding position 11, and a second tray 5b and a third tray 5c are stored at the waiting position 24 in the feed passage 12a. The stepped portion 6 of the first tray 5a located at the winding position 11 is received in the recess 31 of the ejecting plate 26, and the projecting portion 25 of the stopper lever 20 is in contact with the stepped portion 6 of the second tray 5b stored at the waiting position 24 so that the second tray 5b will not be moved to the winding position 11 by the rotary disk 15.
Upon the exhaustion of the cop 4 supported on the first tray 5a, the cam tray 43 of the winding unit 101 turns the shaft 28 through a fixed angle together with the ejecting lever 26 holding the first tray 5a in the recess 31 counterclockwise as shown in FIG. 10 to eject the first tray 5a through the ejecting passage 12b onto the empty bobbin discharging conveyor 2. As the ejecting lever 26 is turned counterclockwise, the roller operating edge 32 engages the free roller 19 supported on the stopper lever 20 to shift the projecting portion 25 of the stopper lever 20 to the left, so that the second tray 5b is allowed to be brought into contact with the roller operating edge 32 of the ejecting lever 26 by the inclined rotary disk 15 continuously and frictionally rotated by the cop feed conveyor 1.
Upon the restoration of the ejecting lever 26 to its initial position, the stopper lever 20 is allowed to its initial position as shown in FIG. 9 and the second tray 5b drops into the recess 31 of the ejecting lever 26 located at the winding position 11. At the same time, the shaft 39 (FIG. 8) is turned so as to open the valve 38 to blow compressed air through the nozzle 35 through the circular slot 34 of the inclined rotary disk 15 and the through hole 10 of the peg 7 into the bore of the take-up tube 8 and, consequently, the free end Yl of the yarn is blown up to the suction pipe. Then, the winding operation is restarted.
In winding the yarn by the winding unit shown in FIG. 8, the absolute value and the amplitude of variation of the yarn tension increases sharply after the amount of yarn on a cop has decreased to a value about 1/3 of that of the yarn of a full cop, namely, after a full cop has reduced to a nearly exhausted cop generally called a 1/3 cop (skinny bobbin), and, in the worst case, the yarn is broken. Furthermore, when the winding speed is increased, sluffing, namely, unstable unwinding of the yarn from the chase 4a of the cop 4 and simultaneous removal of a plurality of coils of yarn from the cop 4, is liable to occur frequently. Increase in the yarn tension and the occurrence of sluffing is dependent on the mode of unwinding of the yarn from the cop 4. A previously proposed method of suppressing increase in the tension of the yarn and the occurrence of sluffing to increase the winding speed limits the size of the balloon of the unwound yarn by a balloon breaker 106 having the shape of a cylinder and provided with a restricting portion and lowers the balloon breaker 106 gradually in the direction of the arrow h as the yarn of the cop 4 decreases. It is found that the balloon breaker 106 suppresses the balloon most effectively when the size e of an annular space formed between the inner circumference of the balloon breaker 106 and the outer circumference of the take-up tube 8 is reduced to the least possible extent. However, the cop 4 must be located at the winding position 11 in an position substantially perpendicular to the inclined rotary disk 15 and a reference plane A defined by the bottom plate 16 to reduce the size e of the annular gap.
However, since the height of the tray 5 is smaller than size of the gap between the inclined rotary disk 15 and the second guide plate 14 in the cop changing mechanism 3 shown in FIG. 8, the weight of the cop 4 tends to tilt the tray 5 and hence it is difficult to hold the cop correctly at the winding position 11 in a position perpendicular to the reference plane A.